The present invention relates to aircraft engine systems and, more particularly, to an electric starter/generator for aircraft, tank engines, and other mobile vehicles.
Existing bridge-type inverter/converter units used to electronically commutate a switched reluctance machine produce direct current electrical power at only one voltage level at a time when in the generating mode. This creates a problem for vehicles that require dc power of at least two different voltage levels, most commonly 270 vdc and 28 vdc.
Present day switched reluctance machines typically generate electric power at one voltage level. However, an electric power system, particularly in a vehicle, may require electric power at two or more voltage levels. One means for providing the two different voltage levels is to use an additional, external converter to convert electrical power from one voltage level to another. Unfortunately, the application of an external converter is an inefficient use of components, since it adds cost and volume to the system and reduces reliability.
It is therefore highly desirable and an object of the present invention to provide multiple voltage levels without the addition of an external converter.
Another object of the present invention is to provide a simultaneous multiple voltage level bridge-type inverter/converter unit for an electronically commutated electrical machine.
Another object of the present invention is to optimize electric power systems to engine and aircraft applications, extending design flexibility.
These objects and other features and advantages will become more readily apparent in the following description when taken in conjunction with the appended drawings.